1. Field of the Invention
The present invention relates to ground anchors, and more particularly to bracing systems that keep modular buildings securely on their foundations during seismic shaking or high winds.
2. Description of Related Art
Modular buildings are usually supported underneath by large steel girders and beams. In California, the bottoms of these beams are permitted to be 12xe2x80x3-36xe2x80x3 above the ground. The typical installation places piers and other supports directly under key points, and these then bear on the ground. Such a pier support is described by James Oliver, et al., in U.S. Pat. No. 5,503,500, issued Apr. 2, 1996.
Some ground is far too soft to place the full load of a support pier on a small patch of soil. So, James Oliver, et al., describe a system of pier support plates that spread the weight over several square feet. Heavy nails are used to pin the system to the ground and prevent side slipping.
A seismic foundation pier with its own ground anchoring is described by the present inventor, Matt Cusimano, in U.S. Pat. No. 5,873,679, issued Feb. 23, 1999. The bottom struts of a pier have pin guides that steer and hold large pinning rods into the ground. Such rods are suggested to be 15xe2x80x3-20xe2x80x3 long, and are driven in with a hammer.
Unfortunately, deep under a modular building, especially just under its support girders, there is very little room to swing a hammer and drive such pinning rods fully into the ground. This situation is exacerbated when the bottoms of the girders are less that 24xe2x80x3 above the ground. What is needed is a pier support system that puts the pinning rods in a better position for a more efficient installation overall.
Briefly, a pier support system embodiment of the present invention comprises a support pier with a load-spreading plate that is laterally braced at the top to an anchor plate pinned to the ground just under the periphery of a modular building. The support pier is placed directly under the support girders of the modular building at critical points, and the lateral bracing runs outboard at a down angle of 35xc2x0-55xc2x0. Sufficient working room exists just inside the periphery of the modular building for large pinning rods to be driven into the ground through the anchor plate.
An advantage of the present invention is that a pier support system is provided that is secure and effective.
Another advantage of the present invention is that a pier support system is provided that is easy to install correctly.
A further advantage of the present invention is that a pier support system is provided that can be economically manufactured.
The above and still further objects, features, and advantages of the present invention will become apparent upon consideration of the following detailed description of specific embodiments thereof, especially when taken in conjunction with the accompanying drawings.